1. Field of the Invention .Iaddend.
This invention is for high-speed testing circuitry particularly useful for the production testing of high-speed electronic devices. .Iadd.
Description of the Prior Art .Iaddend.
.[.It is similar to, but an improvement over that invention described and claimed in.]. U.S. Pat. No. 3,976,940, which was assigned to the assignee of the present invention.[.. This prior art patent.]..Iadd., .Iaddend.describes a computer-controlled testing circuit containing high-speed switching circuitry that applies two predetermined reference voltage levels, representing the two binary states, to an input terminal of an electronic device under test (DUT). When the testing circuit is connected to an output terminal of the DUT, the test stimuli signals produced by another identical testing circuit will produce two-level output signals from the DUT that are compared in the testing circuitry with signals predicted by the associated computer to detect functional errors.
This prior art test circuit materially advanced the state of the existing art by increasing the then upper limit testing frequency from approximately 5 MHz to a greatly improved 10 MHz.
.[.The circuitry of the present invention is a further improvement and is capable of functionally testing electronic devices at a rate of 30 MHz, as will be shown in greater detail hereinbelow..].